1. Field of the Invention
This invention relates in general to grain harvesting combines, in particular to an improved header and feeder for cutting crop from a field and passing a crop to a primary threshing rotor.
2. Description of the Prior Art
A grain harvesting combine has a header which includes a sickle for severing crop from a field, and an auger which directs the crop inward to a discharge port in a rearward portion of the header. The cut crop is then fed upward through a feeder to a threshing assembly which includes a threshing rotor and a perforated housing. The threshing rotor rotates within the perforated housing, passing grain within clearances between the threshing rotor and a perforated housing to thresh grain from the crop. The threshed grain falls through the perforations in the perforated housing onto a grain pan, and from the grain pan onto a set of upper and lower sieves. The sieves are oscillating, causing clean grain to fall through for collection. A blower blows air upward through the sieves, discharging chaff to the rear. Straw from the primary threshing chamber proceeds through a straw beater and out the rear of the combine. The clean grain is collected and conveyed to a storage bin.
Prior art headers for grain combines extend outward on opposite lateral sides of the grain combines and are up to thirty feet in length. Mechanical power for reciprocating the sickle to cut crop and for rotating the auger to pass the crop inward to the header discharge port is provided by a power transfer means located on an outward end of the header. This requires transmission of mechanical power to the power transfer means on the outward end of the header, usually by means of a laterally extending drive shaft coupled to the combine motor by another drive shaft which extends longitudinally along the combine. Mechanical power is transferred by rotating the longitudinally and laterally extending shafts to reciprocate the sickle and rotate the auger. Power is then transferred through the sickle and auger to the portions of the sickle and auger on the opposite end of the header from the outward end at which the drive shaft connects to the power transfer means, the sickle and the auger. Such means for transferring power to operate the sickle and auger is both cumbersome and inefficient.
Prior art feeders typically are provided by conveyor belts, elevators, or some other type of conveyance means, and merely serve to transport the crop from the header up into the combine. Often the crop being passed into the threshing assembly includes stalks which are stiff and rigid. This reduces the speed at which crops may be fed into the threshing assembly, as well as requiring additional forces within the threshing rotor to loosen grain from the straw. This results in slowing down the speed at which crops can be harvested.
Prior art combines typically pass crop from the feeder, through a single port, and directly into the clearances between the threshing rotor and perforated housing. The threshing assembly may include an impeller mounted to the threshing rotor for driving the crop outward into the clearances between the threshing rotor and the perforated housing, and for forcing the crop rearward within the clearances. However, since the crop passes from the feeder and into the threshing assembly through a singular port, crop often loads upon one side of the threshing rotor and is not equally distributed within the threshing assembly.
Prior art impellers include rasp bars mounted to the outermost, outward facing ends defining the outer circumference of the impellers. This typically initiates softening and threshing of the crop, as the crop is pressed into the clearances between the threshing rotor and the perforated housing. Crop is not threshed or softened for passing through the threshing assembly as it passes from the header, through the feeder, and through the forward end of the threshing assembly. Thus, the crop passes through the combine for a significant distance prior to threshing, or softening for passing within the threshing assembly.
The speeds at which combines may be operated for harvesting grain are often limited by the rates at which crop may be fed, or pressed, into the clearances around the primary threshing rotor. Typically, the more rigid the crop that is being fed into the impeller and around the primary threshing rotor, the slower the combine must be operated. Additionally, when crop passes on only one side of the impeller and threshing rotor, crop buildups on the one side of the threshing rotor cause crop jams when grain harvesting combines are operated at faster speeds.